Barq's is my favorite. IBC is also good. Mug and A&W are a bit too sweet for my taste, but they're better than no root beer.

Nothing beats old fashioned Sasparilla though.

A&W has that awesome aged vanilla though, it gives it a sort of "creaminess" to it.

Sasparilla? Neverheard of that. Where can I find it?

I like A&W's cream soda better than their root beer, but hey, any root beer works in a pinch.

Sarsaparilla (I typo'd) is similar to root beer, but is made with Sarsaparilla root instead of Sassafras. It's pretty hard to find in most places, but it can be bought online. I first had it at Wall Drug in South Dakota.